Implement GROUPS frame spec for window functions
Implemented support for the GROUPS frame specification in window functions
by adding :paramref:`_sql.over.groups` option to :func:`_sql.over`
and :meth:`.FunctionElement.over`. Pull request courtesy Kaan Dikmen.
Fixes: #12450
Closes: #12445
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/12445
Pull-request-sha:
c0808e135f15c7fef3a3abcf28465673f38eb428
Change-Id: I9ff504a9c9650485830c4a0eaf44162898a3a2ad
(cherry picked from commit
0bbc515f904446d3f0beede54321b628f32fbdad)